java: correct method name RocksDB.GetColumnFamilyMetaData() (#7606)

Summary:
update GetColumnFamilyMetaData() to getColumnFamilyMetaData()

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7606

Reviewed By: zhichao-cao

Differential Revision: D24610298

Pulled By: cheng-chang

fbshipit-source-id: d24f9b65478da1456f50747637dc95688af874de

java/src/main/java/org/rocksdb/RocksDB.java

@@ -4123,7 +4123,7 @@ public class RocksDB extends RocksObject {
    *
    * @return the column family metadata
    */
-  public ColumnFamilyMetaData GetColumnFamilyMetaData() {
+  public ColumnFamilyMetaData getColumnFamilyMetaData() {
     return getColumnFamilyMetaData(null);
   }